1. Field of the Invention
The invention relates to the formation of a CMOS sensor, and more particularly to the formation of a CMOS sensor structure without blooming effect.
2. Description of the Prior Art
According to FIG. 1, a bird's beak 150 on field oxide area 140 inside the conventional complementary metal-oxide semiconductor (CMOS) sensor structure is a p-type field. Normally this p-type field owns higher concentration leading to leakage current.
For reducing leakage, the concentration of p-type field could be reduced. However, the isolation effect could be reduced as well after the concentration of p-type field is reduced. Thus, the blooming effect and the dark current will happen thus seriously destroying the general function of isolation inside the (CMOS) sensor structure.